I inspected a house today, (1,638 sq ft, standard 3/2 built in 1989) and noted there was an additional air return added in the hall ceiling directly above the floor mounted air return. The ceiling return comes down through a closet to the basement where it connects to the original air return. I couldn’t figure out why there would be a need for this type of configuration. Both air returns were drawing air when the system was operating. Has anyone encountered this kind of setup? The only thing I can think of is the size of the original air return was too small. It’s feeding a 2003 Frigidaire furnace with a 72,000 BTUH input. The floor air return is roughly 10X24 while the ceiling mount air return is 20x20.
My 1,700 SQ. Foot home has 4 returns, one living room, one den, one hall down low and one hall up high. The only reason I mention this is because your system here doesn’t seem odd to me.
I’ve seen multiple air returns before, but never an “after market” addition like this. They took the trouble to route it through the attic and then back down through a bedroom closet to the basement. Looking at the trunk lines in the basement I saw plenty of areas where they could have easily added another return farther down in the hallway floor.
I’ve always thought it would be need to have both registers in the ceiling that blow cold air in the summer and registers in the floor that would blow warm air in the winter, but I never thought I’d see the configuration with air returns.
I would think to help pull the warm air out, that floor return isn’t going to help much with that.
Was there a way to damper the returns?
No sir, no way to damper the returns.
High returns make for better flow with cooling.
The CFM required for each area would require a Manual J calculation which is outside the SOP.
One thing you can do for your own knowledge is count up the supply runs (6" round duct will carry 110 CFM) and a single stud space of 16" is approx.150 CFM. That ceiling return is higher yet but restricted due to in being flex duct in the attic. Then you would have to see where fan speeds/CFM is set.
Supply and return air CFM should be balanced and on a new build, its required.
I would think this is some kind of “balance” arrangement.
Jump ducts in the attic of a 2021 house:
Balanced room returns on a 1954 row home:
Don’t forget the over door Transoms that were in office buildings and homes for years.
There have been and still are lots of different approaches to balancing air flow in a home or building.
I’d bet it’s an attempt at better air circulation - drawing air off the ceiling rather than the floor. A buddy of mine who’s kind of a geek about these things was unhappy with his A/C performance and just had a floor register like in your 2nd picture. He fabricated a 3-sided extension of sorts that essentially elevated the return duct up to the ceiling. He said it made a big difference since the hot air off the ceiling was drawn into the system rather than the cooler air at the floor.
I lived at my last house for 15+ years and it had a terrible duct layout. No exaggeration, my wife would be running the A/C for upstairs and I’d have a fire in the woodstove downstairs (this didn’t happen often but sometimes). The amount of effort that goes into the duct layout in newer tract houses is pathetic. I regularly find houses with 15+ degree differentials between levels. Of course, this is outside of most (all?) SOPs but I definitely try to pay attention to it and let my buyer know when things are really out of whack. It’s definitely easier to tell when it’s either really hot or really cold out and you can somewhat quickly tell how the system is doing.
Hope this post finds you well.
Yes, I have run into returns on ceilings and lower wall assemblies.
Could you please provide the Furnace model number?
As explained, I have seen returns on ceiling and lower wall assemblies in numerous HVAC set-ups. Forced air furnaces, to small water cooled package units in condo’s bathrooms and hallways that are a bugger to inspect.
Forced Air Furnace Summer and Winter return air set-up.
It’s important to remember that hot air rises and cold air falls. In the winter you want the cold air to be drawn through the return registers leaving the hot air behind . By opening the lower registers and closing the top ones you keep hot air in and draw the cold air out.
Hope that helps.
Here’s what I get: Nordyne Furnace Model FG6RA 072C-12A.
Nordyne is the manufacturer for world-class brands like Gibson, Maytag, Mammoth, Reznor, NuTone, Broan, Intertherm, Frigidaire, Miller and Ambirad .
Appears to be an up-flow gas furnace. Correct me if I am wrong.
Robert (Bob) Kennedy post appears to be the closest forced air return arrangement known as a Jumper Duct to balance supply/return.
I can’t add more to his post.
I get manufactured in 2006. FGA03(06)08131
He got it. It’s about air stratification issues.
You can not design an air duct system to operate efficiently in both heating. Depending on the region it is in, we select which is most important, heating or cooling. House design is also considered.
I recommend this all the time, especially a house on a slab (all ducts end up in the ceiling and does not work worth crap). Using a zoned system with dampers is best, but just a duct in the right location is a huge improvement.
Anthony- One obvious issue in this case is that there is no plenum box at the ceiling register. The round dirt spot shows that all the air passes just through the center of the register. As you see, it gets very dirty, which restricts air through the filter and will suck the filter up into the duct, stopping airflow. If this causes excessive static pressure, it can damage the compressor, cause blocks of ice on the evaporator, cause water damage below the air handler. It’s also noisy. Face velocity over about 500 ft/min makes the register vibrate.
Blocking the upper register in winter and lower in summer helps when zone dampers are not installed.
Thank you, David. very kind of you.
4 returns, one living room, one den, one hall down low and one hall up high. Are there returns in the bedrooms?
Sorry. Mistaken. I read bathrooms.
Why should there not be returns in the bedrooms???
Good question, Jeff. System design?
I have returns in my bedrooms.
Sorry Mr. Spence. I read bathrooms. I was not paying attention. My mistake.
Apology, Larry. I read bathrooms.